. American engineer . lvanometer is used, and the apparatus so arrangedthat all readings are taken with the pointer at zero. Theresult of this is that a substantial instrument, little likely tobe affected by the vibration of the train, can be used, and yetaccurate readings obtained. In the installation under noticethe instruments are in duplicate, and the connections for thefour pyrometers are taken to two switches, so that readingsfor all four can be taken on two scales. The reading instru-ments were all in the dynamometer car behind the tender. Inthe diagram. Fig. 1. C represents the cell; G
. American engineer . lvanometer is used, and the apparatus so arrangedthat all readings are taken with the pointer at zero. Theresult of this is that a substantial instrument, little likely tobe affected by the vibration of the train, can be used, and yetaccurate readings obtained. In the installation under noticethe instruments are in duplicate, and the connections for thefour pyrometers are taken to two switches, so that readingsfor all four can be taken on two scales. The reading instru-ments were all in the dynamometer car behind the tender. Inthe diagram. Fig. 1. C represents the cell; G, G represent thegalvanometers, of about ohms resistance; R, R the rheo-stats; A, B, A B scaled resistances; and M M cursors withslide over the scales A B, A B. Two check instruments arealso inserted in the circuits. When taking records the cursorM is moved along the resistance A B until the galvanom-eter pointer is at zero, when the reading of the scale A Bgives a measurement of the temperature. The method of in-. sso i^acuum. Inches of tYafer Fig. 4—Typical Readings Showing How Curves Were Plotted. serting the pyrometer into the large smoke tubes, in order tosecure temperatures at the point T(, is shown in Fig. 3, as isalso the manner in which the connections for this pyrometerwere carried through the boiler shell. The results of some of the experiments are shown in and 5. These are plotted to vertical scales of degrees, andto horizontal scales of smokebox vacuum in inches of 4 shows a typical curve, with the actual points asrecorded. A feature of considerable interest which may be no-ticed in connection with the temperature of the gases leavingthe barrel, is that at the higher rates of working the tempera-ture of the gases leaving the superheater tubes in less than that of the gases leaving the ordinary boiler tubes. This suggeststliat the resistance at the higher rates becomes too greatin the large smoke-tubes for t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1912
